Visual information systems

ABSTRACT

A visual information system includes an array of light emitting elements located at the side of a train track. The elements are individually energizable by a controller in response to a predetermined program stored in a memory and representative of a predetermined visual image. The controller causes selected elements to be turned ON and OFF, some repetitively, in a predetermined sequence as dictated by the program with a time span of 0.015 seconds. A sensor activates the controller upon the approach of a train so that a passenger gazing at the array as the train passes will perceive the image apparently extending over an area substantially greater than the area of said array.

FIELD OF THE INVENTION

The present invention relates to visual information systems.

BACKGROUND OF THE INVENTION

Advertising is often presented in illuminated form consisting of anarray of fluorescent lights. Such lights are usually switched on duringthe hours of darkness. The array occupies the same area as the imagepresented and consumes relatively large amounts of energy. Such systemsare relatively inflexible in as much as the whole array needs to berebuilt to display another image.

Other arrays of moving images are known in which an array consisting ofa plurality of rows and columns of light sources are individuallyenergizable to produce, for example, a moving message. Such arrays haveseveral times more columns of light source than rows. Also, the size ofthe array is the same size as the image and consequently the wiring ofindividual light sources to the controlling circuitry and the complexityof the control circuitry are likely to be very costly.

It is an object of the invention to provide an improved visualinformation system.

SUMMARY OF THE INVENTION

According to the present invention there is provided a visualinformation system comprising an array consisting of a plurality ofindividually and selectively energizable light sources arranged in rowsand columns, a memory for storing a program representative of apredetermined image, a controller actuatable to control the selectionand sequence of energization of the light sources within a predeterminedtime span in accordance with the predetermined program stored on thememory so that a viewer observing the array and being carried past thearray at a predetermined speed will observe immediately following saidpredetermined time span the predetermined image as an apparentlystationary image occupying an area substantially larger than the area ofsaid array.

According to the present invention there is further provided a visualinformation display system comprising a fiber optic array in which oneend of a bundle of optical fibers is arranged so that the ends of theindividual fibers at one end of the bundle form a vertically elongatearray of rows and columns and the ends of the individual fibers at theopposite end of the bundle are connected to an electro-optical interfaceunit, and means for supplying electrical signals to the interface unitto cause the array to display a succession of images in sufficientlyquick succession that a viewer being carried past the array perceives asingle horizontally elongate display consisting of said successiveimages located side by side.

BRIEF DESCRIPTION OF THE DRAWINGS

Visual information system embodying the invention will now be described,with reference to the accompanying diagrammatic drawings, in which:

FIG. 1 is a front elevation of the system;

FIG. 2 is a block diagram of the system;

FIG. 3 is a more detailed block diagram of the system;

FIG. 4 is a block diagram of another form of system embodying theinvention; and

FIG. 5 is an end view of a train passing through a tunnel andillustrating the positioning of the system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The visual information system to be described is arranged to be locatedin tunnels through which public transportation vehicles such as tubetrains normally run. The system consists of a series of light sourcearrays 2 arranged at spaced intervals along the track 4 on the side wallof the tunnel, generally level with the windows of the train so that thearrays can be viewed by the passengers in the train. A sensor 6 locatedupstream of each array 2 is responsive to the approach of the train tothe array to actuate the array. Another sensor 8 located downstream ofeach array is responsive to when the train has passed to deactivate thearray 2. The sensors 6 and 8 may take the form of infrared transmitterand receiver pairs.

Each array 2 consists of four columns and sixty four rows ofindividually and selectively energizable light sources for example lightemitting diodes.

Selected light sources in the array are switched ON and OFF by acontroller 10 in accordance with a predetermined program stored in amemory 12. The controller is triggered by the sensor 6 and the programis cyclically repeated until a signal is received from the sensor 8.

The switching rate of the light sources and the duration of theirenergization is such that a passenger sitting in the train and keepinghis eyes directed at the array will observe an image several times widerthan the width of the array.

The effect is achieved because with light flashes of very shortduration, the reaction of the human eye to the flash persists long afterthe flash has finished. Thus, where a series of very short flashes occurover a short time span less than 0.015 seconds, all the flashes appearto the eye to have occurred at the same time and when the flashes arespaced from one another on the retina because the viewer has movedrelative to the array, the eye perceives a composite light pattern whichwill persist for a short time while immediately following the time span.It will thus be appreciated that a program can be created and stored inthe memory 12 which will produce almost any desired image for theobserver. The image may take the form of alpha numeric information ormay take the form of an advertising poster.

The block diagram of the system is more clearly shown in FIG. 3.

As can be seen, the array 2 consists of a series of light emittingdiodes 20. In this arrangement only sixteen are shown, arranged in asingle column. Each LED has a power output of 32 mcd's and has a highswitching speed with a switching time faster than 10 nanoseconds.

The controller 10 includes a driver 22 which acts to drive the LED's 20through respective resistors 24. The driver 22 is controlled by acentral processing unit (CPU) 26 which derives its instructions fromterminal 1 of the memory 12 via resistors R36 and R34 which feedterminal 5 of the CPU. The memory 12 is in the form of an erasableprogrammable read only memory (EPROM).

The CPU 26 is triggered into action by a signal received on terminal 28from the sensor 6.

The CPU cyclically repeats the program stored in the EPROM 12 at arepetition rate in the range of from 10-50 Hz but is preferably 15 Hz.

By updating the memory periodically the passengers will be able toobserve different images.

When a large plurality of arrays are provided they can be divided intogroups with the memory of the system in each group being updatablesimultaneously. A central computer (not shown) is provided to store aplurality of different programs. The central computer is connected toeach group to update the memory in each group with a new programdepending either upon the time of day or the location of the group.

When a color image is required, each light source of the array can bereplaced by a row consisting of red, green and blue elements or a rowconsisting of red, green, blue and white light elements. Each element isselectively energizable. It will be appreciated that by having theprogram determine the period of energization of each light source, theshade of color in the final image can be varied as required.

While the rows and columns in each memory can be varied, it ispreferable that the ratio of rows to columns in the array is 16:1 orgreater.

In the embodiment shown in FIG. 4, the optical array 20 consists of anarray formed by the exposed ends of a bundle 22 of optical fibers. Theopposite ends of the electro-optical fibers of the bundle 22 areconnected to an electro-optical interface unit 24. Data representativeof a desired image to be displayed is transmitted from a centralcomputer 32 by radio optical or direct wire link to a data interfaceunit 30 which passes the signals to a processor 28 which in turn causesthe signals to be stored in a storage unit 26. The processor 28 isresponsive to a local trigger such as the sensors 6 and 8 described inconnection with FIGS. 1 and 2 or a remote trigger, to cause theelectro-optical interface to read out the stored data from the memory 26and to cause the corresponding image to be progressively reproduced onthe display 20 in a manner such as that described in conjunction withFIGS. 1 to 3.

The central computer 32 can be programmed to send different displays todifferent groups of optical arrays as required and alter the displaysstored by the memories 26 at different times of the day, week and/ormonth.

In the embodiment shown in FIG. 5, a train 36 within a tunnel 34 carriesan on-board transmitter 38 which is connected to an on-board or a remotecentral computer 32. Data from the computer 32 is transmitted by thetransmitter 38 to a receiver 40 adjacent a display 20 mounted on thewall of the tunnel. The receiver is connected to the data interface 30(see FIG. 4) of the display from whereon the system operates in the samemanner as described in connection with FIG. 4.

The transmitter and receiver may be acoustic, optical or radio. Also,the train may have an on-board speed monitor and data representative ofthe speed of the train transmitted to the processor 28 so that theprocessor can modify the rate that the electro-optical interface readssignals from the memory 26 in a manner to synchronize the display withthe speed of the train.

In a modification, instead of the interface 24 reading signals from thememory 26, the memory 26 can be omitted and the signals read in realtime from the processor 28.

What is claimed is:
 1. A visual information system for use in connectionwith a carrier for carrying observers along a predetermined path, thesystem comprising an array to be located adjacent said path andconsisting of a plurality of individually and selectively energizablelight sources arranged in rows and columns, a memory for storing aprogram representative of a predetermined image, a controller actuatableto control the selection and sequence of energization of the lightsources within a predetermined time span corresponding to persistenttime of a human retina to light, and in accordance with thepredetermined program stored in the memory, a rate of operation of thecontroller being set to correspond with a speed of the carrier past thearray such that an observer carried by the carrier past the array willobserve said predetermined image as an apparently stationary imageoccupying an area substantially larger than the area of said array.
 2. Asystem according to claim 1, including sensing means for monitoringpassage of the carrier carrying said observer past the array to actuatesaid controller.
 3. A system according to claim 2, wherein said sensingmeans comprises infrared sensing means arranged to activate saidcontroller upon approach of said carrier to the array and to deactivatethe controller upon departure of said carrier away from said array.
 4. Asystem according to claim 3, wherein the sensing means comprises a firstinfrared transmitter and receiver pair located upstream of the array anda second infrared receiver and transmitter pair located downstream ofthe array.
 5. A system according to any preceding claim, wherein thecontroller is arranged to cyclically repeat the energizations specifiedby the predetermined program at regular intervals.
 6. A system accordingto claim 1, wherein the array consists of light sources of differentcolors and wherein the predetermined program specifies differentdurations of energization of the different colored light sources.
 7. Asystem according to claim 1, wherein said controller is arranged tocomplete one cycle of the predetermined program within a period of 0.015seconds.
 8. A system according to claim 1, wherein a ratio of rows tocolumns in the array is 16:1 or greater.
 9. A system according to claim1, wherein each light source comprises a light emitting diode and thecontroller includes a driver for driving each light emitting diode, thedriver being arranged to vary a period for which its corresponding diodeis energized in accordance with the program stored in the memory.
 10. Anarrangement comprising a plurality of systems each according to claim 1and a main computer arranged to store a plurality of different programs,each program representing a respective image, said main computer beingoperable to replace the program stored in said memories with a programstored in said main computer.
 11. An arrangement according to claim 10,wherein said main computer is programmed to replace the program storedin selected ones of the memories in accordance with the time of day. 12.An arrangement according to claim 10 or claim 11, wherein the computeris programmed to replace the program stored in selected ones of thememories in accordance with a location of their associated arrays.
 13. Atransport system having a path along which carriers can pass and avisual display system located adjacent said path, the display systemcomprising a fibre optic array in which one end of a bundle of opticalfibers is arranged so that ends of the individual fibers form avertically elongate array of rows and columns and ends of the individualfibers at the opposite end of the bundle are connected to anelectro-optical interface unit, control means for supplying electricalsignals to the interface unit to cause the array to display a successionof images and means for controlling the rate at which the control meanssupplies said signals in accordance with a speed of a carrier past thedisplay system, and within a time frame related to a persistent time ofa human retina to light, such that an observer on the carrier willperceive apparently simultaneously a single horizontally elongatedisplay consisting of said successive images located side by side.
 14. Atransport system according to claim 13, wherein the control meansincludes a computer for generating data representative of a desireddisplay, a local data interface for receiving the data, and a processorfor processing the received data and storing it in a memory, theprocessor being arranged to control the interface unit to respond to thedata stored in the memory.
 15. A transport system according to claim 14,wherein the carrier is a train, the path is defined by a train tunnel,and the array is mounted on a wall of the train tunnel and furthercomprising an on-board transmitter on a passing train to transmit thedata from the computer to supply the interface unit with said data.